Printed circuit boards are usually made by an etching method. A resin-impregnated insulating base, lined with a metal foil, is used. The desired conductor paths are covered by lacquer on the metal foil and those areas of the metal foil which are not covered are then caustically removed.
Printed circuit boards made in this way are relatively expensive. The base both insulates and constitutes a carrier for the conductor paths and is, therefore, usually made relatively thick. Generally, a phenolic resin is used to impregnate the insulating base. If several printed circuit boards are arranged one above the other, relatively thick and heavy packs result. It is of particular importance that printed circuit boards of this type must be treated as separate waste during disposal.
DE-PS 47 86 66 describes a method for making printed circuit boards by affixing conducting structures stamped out of sheet metal to an insulating base. In order to enable the stamped conductor paths to be held together, metal connecting straps are left between the conductor paths and are removed after the conducting structure has been fastened to the insulating base. Due to the fact that these connecting straps are removed, the mechanical stability of the printed circuit boards is determined solely by the insulating base, so that these must also be made relatively thick when using this method.